Geotextiles in Embankment Dams - Association of State Dam Safety ...

Geotextiles in Embankment Dams3.1.2 Internal chimney and horizontal blanket drainsGeotextiles have been used in a limited number of applications as the filteringelement or in conjunction with conventional graded granular filters in drainageapplications within dams (figs. 3.3 through 3.5). Drainage capacity is necessary tolower the phreatic surface in dams for improved slope stability of the embankmentor simply located to control nuisance seepage that can sustain a wet toe or abutmentof a dam and/or downstream wet area. Filters protect the upstream soil from beingeroded into the drain.Figure 3.3.—Illustration of a chimney filter and drain incorporating a geotextile filter. Thisconfiguration is not consistent with accepted practice by most dam engineers.Figure 3.4.—Illustration of a blanket drain incorporating a geotextile filter. Thisconfiguration is not considered as accepted practice by most dam engineers.60